Reuse mod_ajp_proxy connections

[Dimitar Georgievski <mitkany@xxxxxxxxx>]

Hello,

We have a Tomcat 5.5.25 server connected to Apache 2.2.9 over mod_ajp_proxy. Monitoring of the servers shows that AJP proxy connections are not reused but closed and reopened. Frequent closing of TCP connections leaves many connections in TIME_WAIT state and this is something we would prefer to avoid if possible.

While reviewing of Apache, Tomcat and mod_proxy settings I found that the response from Tomcat contains a flag that indicates if the TCP connection should be reused after the end of a request-handling cycle. 

http://httpd.apache.org/docs/2.2/mod/mod_proxy_ajp.html#resppacketstruct (See Response packet structure)

My understanding of the reuse flag in AJP13_END_RESPONSE structure is that this flag is hard coded and cannot be controlled by configuration settings. Am i right? I couldn't find any in Tomcat AJP connector configuration that could do change the value of this setting.

The ProxyPassMatch directive is using all the default settings for the proxy connection

ProxyPassMatch ^/(.*) ajp://localhost:8009/$1

Apache is configured to use mpm workers. The following are Apache compile settings:

# bin/apachectl -V

Server version: Apache/2.2.9 (Unix)

Server built:   Jun 21 2008 18:48:38

Server's Module Magic Number: 20051115:15

Server loaded:  APR 1.3.2, APR-Util 1.3.2

Compiled using: APR 1.3.2, APR-Util 1.3.2

Architecture:   64-bit

Server MPM:     Worker

  threaded:     yes (fixed thread count)

    forked:     yes (variable process count)

Server compiled with....

 -D APACHE_MPM_DIR="server/mpm/worker"

 -D APR_HAS_SENDFILE

 -D APR_HAS_MMAP

 -D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)

 -D APR_USE_SYSVSEM_SERIALIZE

 -D APR_USE_PTHREAD_SERIALIZE

 -D SINGLE_LISTEN_UNSERIALIZED_ACCEPT

 -D APR_HAS_OTHER_CHILD

 -D AP_HAVE_RELIABLE_PIPED_LOGS

 -D DYNAMIC_MODULE_LIMIT=128

 -D HTTPD_ROOT="/local0/tmp/new_build/obj/x86_64-linux-glibc2/apache2.2"

 -D SUEXEC_BIN="/usr/local/covalent/apache2.2/bin/suexec"

 -D DEFAULT_SCOREBOARD="logs/apache_runtime_status"

 -D DEFAULT_ERRORLOG="logs/error_log"

 -D AP_TYPES_CONFIG_FILE="conf/mime.types"

 -D SERVER_CONFIG_FILE="conf/httpsd.conf"

Thanks,

Dimitar